Arachidonic acid metabolism in heat-shock treated human leucocytes

Human neutrophil granulocyte fractions (PMN) and lymphocytes/monocytes/basophils (LMB) were stimulated with A23187 (7.3 microM), opsonized zymosan (1 mg) or FMLP (10(-5) M) after heat-shock treatment. We observed a temperature- (pretreatment over 40 degrees) and time-dependent (incubation periods longer than 20 min) suppression in the generation of LTB4, LTB4 metabolites and isomers, as well as LTC4 and 5-HETE. These effects were not reversed after the addition of exogenous arachidonic acid (AA;50 microM). In contrast, heat-shock treatment alone triggered platelets to generate 12-HETE. After 1 hr at 42 degrees, 135 +/- 24 ng of 12-HETE were generated from 1 x 10(8) cells. The 12-HETE generation was not dependent on extracellular Ca2+. Conversion of 14C-AA (2 nmol) revealed an enhanced metabolism of AA to 12-HETE by platelets after heat-shock treatment without exogenous Ca2+. PMN and LMB labelled with 35S-methionine led to heat-shock protein (HSP; 65,000, 83,000 MW) expression after heat-shock treatment at 42 degrees or in the presence of NDGA (1 x 10(-5) M) at 37 degrees. These results suggest a regulatory interaction between the generation of lipo-oxygenase products, cellular stress responses and the expression of HSP.